Interfacial phenomena, both desirable and detrimental, are central to many processes in animal cell bioreactors; however, these phenomena in bioreactors and bioprocesses are poorly understood. Currently, the use of surfactants are crucial to the large scale (greater than 100 L) cultivation of suspended animal cells in sparged bioreactors (a multibillion dollar a year industry). However, these surfactants were empirically chosen and are far from being optimum. The proposed research is to screen a large number of highly purified surfactants with the ultimate goal of developing more optimum surfactants for use in animal cell culture. This will involve screening for the effect of the surfactants on cells, the ability of the surfactants to inhibit foaming, the ability of the surfactant to prevent cell adhesion to gas-liquid interfaces, and the effect of the surfactant developed to assist in the selection of proper surfactants. PROPOSED COMMERCIAL APPLICATION Surfactants are presently used in commercial tissue cell culture production of, mostly pharmaceuticals wherein sparging of oxygen is required. Without the use of surfactants in many systems the yields are low or nil. With a better surfactant yields would increase resulting in improvement of efficience and profitability.